Interpretive Summary: Small beef processing plants that harvest less than 1000 cattle per day produce a significant portion of the U.S. beef supply. However there is little information available about E. coli O157:H7 and Salmonella in these processing plants. These data are needed for these plants to establish benchmark numbers to compare themselves to, as well as by policy makers. To address this lack of data, hides and carcasses of cattle at seven small processing plants located across the U.S. were analyzed for the prevalence and amount of E. coli O157:H7 and Salmonella. Results showed that there was significant plant-to-plant variation in both the levels and prevalence of pathogens on hides and carcasses before microbial interventions were applied. Reduced levels of pathogens on carcasses were noted among small processors that had incorporated a hide-directed intervention. The results observed in the small processing plants are comparable to those previously observed in larger processors, showing that smaller beef processors face and address the same challenges as larger beef processors.

Technical Abstract: A significant portion of the U.S. beef supply is produced in beef processing plants that harvest less than 1000 cattle per day. However there is little data on the prevalence and levels of E. coli O157:H7 and Salmonella in these processing plants. To address this lack of data, hides (n=1995) and carcasses (n=1995) of cattle at seven small processing plants located across the U.S. were analyzed for E. coli O157:H7 and Salmonella. Across all plants, hide prevalence of E. coli O157:H7 and Salmonella was 71% and 91%, respectively. Twelve percent of hides had E. coli O157:H7 at enumerable levels (=40 CFU/100 cm2), while 36% of hides had Salmonella at enumerable levels. Across all plants, the prevalence of E. coli O157:H7 on pre-evisceration carcasses was 33%, with 2% at an enumerable level (=0.8 CFU/100 cm2). Across all plants, Salmonella prevalence on pre-evisceration carcasses was 58%, with 8% at an enumerable level. Significant plant-to-plant variations in levels and prevalence of pathogens on carcasses were detected. Reduced levels of pathogens on carcasses were noted among small processors that had incorporated a hide-directed antimicrobial intervention. The results obtained are comparable to those observed for larger processors, showing that smaller beef processors face and address the same challenges as larger beef processors.